/*
 * http://code.google.com/p/simple-lexing-parsers-4-scala/
 * 
 * Copyright (c) 2011, Sanjay Dasgupta
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package slp

trait StandardTokenParsers extends SimpleLexingParsers {
  
  def keyword(chars: String): Parser[String] = throw new IllegalAccessException("Use 'literal()' instead")
  lazy val numericLit = {
    if (numericLit$ eq null)
      lastCallForTokens()
    numericLit$
  }
  lazy val stringLit = {
    if (stringLit$ eq null)
      lastCallForTokens()
    stringLit$
  }
  lazy val ident = {
    if (ident$ eq null)
      lastCallForTokens()
    ident$
  }

  private var numericLit$: Parser[String] = null
  //  elem("number", _.isInstanceOf[NumericLit]) ^^ (_.chars)
  private var stringLit$: Parser[String] = null
  //  elem("string literal", _.isInstanceOf[StringLit]) ^^ (_.chars)
  private var ident$: Parser[String] = null
  //  elem("identifier", _.isInstanceOf[Identifier]) ^^ (_.chars)
  
  override protected def lastCallForTokens() {
    numericLit$ = "[0-9]+".r
    stringLit$ = "\\\"[^\"\n]*\\\"|\\\'[^\'\n]*\\\'".r ^^ {s => s.substring(1, s.length - 1)}
    ident$ = "[a-zA-Z_][a-zA-Z_]*".r
  }
  
}
